The present invention relates generally to packages in tube form, which are traditionally used for the packaging of pasty products such as dentifrice, pharmaceutical products, creams and various cosmetology products, food products, glues, mastics, etc.
A general problem encountered in ordinary use of tubes lies in the fact that it is impossible to empty them completely of their contents, resulting in a loss of packaged product, with unavoidable negative effects from both the economic and the ecological standpoints.
A tube is diagrammatically described in the patent document DE-2914370 in order to solve this problem.
Although the solution proposed by this patent, which consists of reducing the angle between the neck and the axis of the tube, is both useful and relatively effective, the adjustment of the parameter constituted by this angle does not enable one to solve the problem mentioned above in all the cases in point, that is to say with tubes of various sizes, consisting of different materials and enclosing products of various viscosities.
Furthermore, known, for example, through patent documents WO 96/30272 and FR 2 105 590 are flexible tubular bottles which, although they have considerable variations of thickness according to a transverse direction, aim to solve the same problem.
In reality, these containers not only pose relatively intense manufacturing problems but they are also found to be subject to an unsolvable compromise between the risk of air tightness failure of the zones of lesser thickness, with the need, in order to avoid this risk, to increase the extra thickness of the zones of greater thickness, and the industrial need to produce tubes with a minimum of material.
The invention is situated in this context and proposes a tube which empties completely, making it possible to palliate the limitations and problems mentioned above.
The invention more precisely relates to a packaging tube which has: a tubular skirt elongated in an axial direction, the skirt having a filling end closed off by collapsing of the skirt in a transverse direction and forming a first end of the tube; and a head situated at a second end of the tube, away from the filling end, the head having a channel for distribution of the pasty product and a neck in the form of a radial extension of the distribution channel, the neck being connected to the skirt by a connecting surface, the connecting surface having, in a longitudinal plane containing the axial direction and perpendicular to the transverse direction, a particular minimum radius, and the skirt having, in a plane transverse to the axial direction and situated midway between the ends of the tube, a particular circumference and a roughly constant thickness.
For this purpose, the tube of the invention is characterized by the fact that the ratio of the particular circumference to the minimum radius is less than twenty (that is to say less than 6xcfx80) and preferably at most equal to ten (that is to say barely over 3xcfx80).
Furthermore, with respect to the axial direction, the neck preferably has a maximum inclination less than 60 degrees.
In practice, it can prove useful to give the connecting surface, with respect to the axial direction, a maximum inclination of, at most, 45 degrees or even, at most, equal to 30 degrees.
In order to make the tube of the invention even easier to use, it is moreover possible to make the ratio of the average thickness of the neck to the average thickness of the skirt at most equal to 2.
According to a preferred embodiment, the skirt and the head are produced in the form of a single piece, without a connecting zone.
In the case corresponding to a preferred application of the invention, and in which the tube is produced by injection of a thermoplastic material and must be made air tight in order to ensure the protection of its contents, this tube is preferably covered on its whole surface, including the head, with a protective varnish called a xe2x80x9cbarrier varnish,xe2x80x9d for example, deposited by spraying.
Contrary to the prior art, in which the tube skirts are obtained by extrusion, it is possible in the invention to define the skirt by a generating line not parallel to the axial direction of the tube.
Finally, the ease of use of the tube of the invention is further improved by choosing, for the skirt and the head, an elastically extendible material having very satisfactory flexibility.